Just my .02
Sattelites as Warp Point defences IMO should have direct fire weapons on them. As you found, missles don't do well 'cause they 'release' the missles then they get shot down with the PD. Try using your highest level direct fire weapon and you'll probably have better success.
Especially since sat's can be targeted by more than just PD; most direct fire weapons can target them as well. 1 or 2 hits from Massive Mount PPB's can wipe that whole stack of 100 sat's out in 1 turn. Then the PD picks off ypour missles in the same turn! Results; not good.
